1. Field of the Invention
This invention relates to determining material composition, and more particularly to a method and a structure for determining one or more component concentrations contained in a material. 2. Description of the Related Art
The following descriptions and examples are not admitted to be prior art by virtue of their inclusion within this section.
Compositional analysis of materials is desirable for many applications. For example, the type of adhesive applied to a tape product or the type of metal or paint applied to a product for corrosion protection is critical for the functionality of the products. The method and structure described herein are discussed primarily with respect to the analysis of thin films within semiconductor devices. The term “thin film” is commonly used within the semiconductor industry when referring to layers deposited upon a semiconductor wafer during the fabrication of a transistor. Specialized materials are selected for thin films to perform specific functions of the transistor. In order for a thin film to be effective, it must conform to strict electrical, chemical, and structural requirements. Thin film materials may include, but are not limited to, metallic, semiconducting, and dielectric materials or a combination of such materials. Often, thin films are doped with impurities to heighten the effectiveness of the material used.
Inaccurate analysis of one or more process parameters within the fabrication of a semiconductor device, such as a transistor, may hinder or prohibit the function of the device, leading to a reduction in production efficiency and device quality. The characterization of thin films is especially important, since the effectiveness and reliability of thin films play an important, central role in the operation of a semiconductor device. Therefore, thin films must be accurately analyzed in order to meet a semiconductor device's functionality requirements. In addition, as production volumes and efforts to improve process control increase in the integrated circuit fabrication industry, the ability to accurately characterize semiconductor processes and the materials associated with such processes in a timely manner becomes more critical.
At present, it is difficult to find an analytical technique suitable for use in semiconductor fabrication that can characterize the composition of a thin film in a simple, accurate, and cost-effective manner. Many current techniques require large pieces of equipment, such as spectrometers that are not used within a fabrication area due to size and cleanliness requirements. Some of these techniques may include, for example, Secondary Ion Mass Spectroscopy (SIMS), Auger Electron Spectroscopy (AES), and X-ray Photoelectron Spectroscopy (XPS). In addition, current techniques typically employ expensive equipment, thereby increasing the fabrication cost of the semiconductor devices. In some cases, a manufacturer may decide to forego the additional costs of purchasing a piece of analytical equipment and send samples to an outside testing facility. Such an option requires additional time for the analysis to be conducted. Often, the amount of time required for such an outside analysis is on the order of a few days or weeks. As a result, production throughput and efficiency is sacrificed due to the increased process cycle time of the devices. Consequently, many current analysis techniques do not coincide with the desire within the semiconductor fabrication industry to increase production efficiency and improve process control.
It would, therefore, be advantageous to create a method and a structure with which to determine the composition of a material in a simple, accurate, and cost-effective manner. Such a method and structure would be particularly beneficial for determining the concentrations of an impurity within a thin film of a semiconductor device.